Remive mildew and stain from canvas awning
Spray with mold mildew remover and powerwash
Here's a post that might help you - https://www.wikihow.com/Remove-Mildew-from-Canvas-Awnings
Hi Claudia. If you are able to remove the canvas I would do that. Then use a big tote or garbage can and fill it with water and about 1 cup of outdoor bleach, and mix well. Put the canvas in the mixture and let it soak for a while then rinse. It work on boat cushions for me. If you can remove it try scrubbing it with a good scrub brush and dish soap and water.Good Luck!
Here's a great article on removing mildew from awnings.